Low battery will cause flaky stuff and problems, "INTRODUCTION" and "AFTERMARKET BATTERY" has nothing to do with it and will not cause electronic problems.
At the end of the day if one is cheap a$$ and practical like me, they will just throw the biggest "AFTERMARKET" battery that will fit in there and replace it at the first sing of decay. In California that is, in a colder climates i will replace it before the second winter and call it a day. $200 for 1.5-2 years for a battery is nothing in the great scheme of things owning E70 X5 in any form.